extending NAT

Joseph Mack mack.joseph at epa.gov
Thu May 2 12:44:53 BST 2002

Wayne wrote:

> >Server->Director->Client: address pair (SIP, DIP) is changed to (DIP, CIP).
> Do you have to allocate a table for tracking these changes, too?
> That will further slow down the director.

I talked to Wensong about this in the early days of LVS, but I remember
thinking that keeping track of the CIP would have been a lot of work.
I think I mentioned it in the HOWTO for a while. 
However I'd be happy to use the code if someone else wrote it :-)

Some commercial load balancers seem to have some NAT like scheme where
the packets can return directly to the CIP without going through the director.
Does anyone know how it works? (Actually I don't know whether it's NAT-like
or not, I think there's some scheme out there that isn't VS-DR which 
returns packets directly from the realservers to the clients - this
is called "direct server return" in the commercial world).

Joseph Mack PhD, Senior Systems Engineer, Lockheed Martin
contractor to the National Environmental Supercomputer Center, 
mailto:mack.joseph at epa.gov ph# 919-541-0007, RTP, NC, USA

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